Oh, aye. Reporting food hoarders was a major national pastime in both the US and the UK during both world wars. Hoarding food, expecially controlled foods such as sugar, fats, and flour, was considered to be a form of treason. Even allowing leftover food to spoil, or throwing away uneaten something that had gotten burnt or otherwise spoiled in the cooking, was considered tantamount to aiding and supporting the enemy. My Granny had a fund of stories from the wars about such things, and my mum still can recite rhymes that were written and broadcast on the airwaves to help teach children not to waste food.

More generally, citizen vigilante groups like that have often flourished during wartime, and often get either overt or covert government support. Which is rather horrible, really.